The Biospecimen Core will work closely with SPORE investigators to enhance their projects by supplying quality controlled colon and esophagus tissues and expert consultation regarding multiple aspects of pathology. A longstanding collaboration between members of the Biospecimen Core and individual project investigators has resulted in the compilation of an extensive tissue archive of cancers from 2,443 patients with primary colon cancers of known pathological state and data based clinical follow-up. A substantial archive of paraffin blocks of normal, pre-cancer and cancer specimen, including metastases of regional lymph nodes, distant organs and subsequent recurrences is maintained. Frozen material with matched normal controls from 887 of these cases is banked. There are 444 esophageal cancers and Barrett's esophagus paraffin specimens and 202 frozen esophageal specimens. Historically, the Core has supplied Gl SPORE investigators with microdissected esophageal and colon cancers suitable for analysis of the temporal sequence of gene mutations, colon cancer tissue arrays suitable for immunohistochemistry and in situ hybridization, frozen tissue suitable for RNA profiling, and blood specimens for genotyping in the discovery of novel inherited traits of colon cancer predisposition. The core also banks blood specimens for future biomarker development. Additionally the Core will: i) organize and distribute all prospective Gl biospecimen procedures to SPORE investigators; ii) provide access to its existing tissue archive resource; iii) identify tissues of interest from archive and prospective accrual to investigators; iv) manage biospecimens obtained by Individual projects for later targeted investigation; v) provide histopathological quality control for tissue sections with project specific morphology case reviews and oversee and provide longitudinal follow-up of clinical outcomes linked to these tissues; vi) provide tissue microarray sections for tissue targets of interest; and vii) provide expertise in immunohistochemistry assessment and samples appropriate for specific studies. The primary objective is to provide a resource that contributes significantly to individual project goals and cooperation between other Gl SPOREs